Fetal bovine serum (FBS) is currently the gold standard in regard to a natural fluid that is rich in a mixture of growth factors. As such FBS is used as an essential ingredient for tissue culture of all types of mammalian cells. The most important commercial uses of FBS are in research and manufacture of viral vaccines for human and animal health. It is obtained from the fetuses of pregnant cows at the time of slaughter. Since the serum is derived from a rapidly growing tissue it is unique in its high content of tissue growth factors and a host of differentiation factors which are responsible for maintaining the natural properties of cells in culture. Even though a reagent of choice, the use of FBS involves the risk of transmission of the mad cow disease via the FBS harvested from infected cows during times of disease outbreak. Further, the method of obtaining FBS by slaughtering unborn calves has raised serious ethical problems, restricting the supply of this essential biomaterial. It is important that a substitute be found that could be less expensive, and avoid slaughtering unborn fetuses.
The cell culture industry is responding to these needs by developing specialized formulations containing manufactured growth factors and other proprietary ingredients tailor-made for culture of specific cells. Despite the addition of known factors, these formulations also contain FBS, albeit in lesser amounts. Presently, such formulations are three to four times more expensive than media made from FBS.
As commonly understood, stem cells are ‘mother’ cells that can multiply and differentiate to many different types of cells that make up the many organs and tissues. Such stem cells are derived from the blastocyst, a small tissue formed days after conception. Although multipotent, the use of these cells, because of their fetal origin, is opposed by many societies in the world on ethical grounds. Even though their potential power to regenerate all tissues is exciting to researchers their clinical use is at present fraught with safety concerns. The main safety problem with these cells is that when injected these cells become tumors because, at present, the natural cues which exist in a developing fetus cannot be replicated in a patient. Adult stem cells, on the other hand, are derived from adult organs such as bone marrow, fat, hair and other tissues in which they lie in a dormant state. This is currently an active area of research and investigators are finding such cells in more and more tissues. These cells are safer to use because they do not form tumors when injected. Their potency to form other tissues is at present limited to fat, cartilage and bone. Whether they can form other tissue is debatable. However, they have been shown to improve healing and repair damaged and diseased organs. Such knowledge of their potency has mainly come from studies of the bone marrow derived stem cells. It is unclear how the different stem cells obtainable from the various organs compare in their potency to heal and repair damaged tissue. It is therefore important to search for newer sources of adult stem cells because it is possible that an adult stem cell, either lying dormant in a tissue or inducible by experimental means, may be found that could be comparable to the embryonic stem cells in potency and yet be safe to use.